1. Field of the Invention
The invention concerns a process and a device for concretizing deep, vertical shafts, wherein concrete is conveyed from above ground to a lower lying application site via a cement column contained in a downpipe.
2. Description of the Related Art
Shafts, as they occur in mines, which are to be concretized in accordance with the inventive process, have a depth of, for example, 500 m and more. When the concrete is allowed to drop uncontrolled in the downpipe, there is the danger of separation (demixing) and congestion. This applies also in the case when detours are provided within the downpipe. The conveyance of concrete purely by gravity into such deep shafts is associated with high frictional wear, even if a series of sliding gates are provided along the drop zone, which are periodically switched. Further, the sliding gates which are conventionally available do not provide reliable performance due to the high frictional wear during switching by the abrasive concrete and the large number of necessary switching procedures.
Beginning therewith it is the task of the present invention to develop a process and a device for concretization of deep, vertical shafts, with which a reliable transport of the concrete to the application site is accomplished without demixing and with the greatest possible operational reliability.
The inventive solution is based upon the concept of a procedure in which the concrete is removed in portions at the outlet side of the downpipe and separated from the following concrete column, and thereby is removed from being under pressure, and then is conveyed or supplied to the application site. In order to accomplish this, it is proposed in accordance with a preferred embodiment of the invention that the concrete column at the outlet end of the downpipe is conveyed to a cylinder, and there is supported in this cylinder by a piston, which piston yields, thereby increasing the cylinder volume, such that the cylinder content, after the piston reaches the piston end position, is separated from the remaining concrete column, and thereafter preferably with advancing of the piston is pushed out of the cylinder directly or indirectly to the application site. In the case of indirect application, the concrete is preferably conveyed to a buffer container and from there is delivered on to the application site. The concrete which is not under pressure is preferably delivered to the application site via a further drop zone, which is shorter than the concrete column, and is formed for example by a distribution hose.
Technically speaking, the described cylinder arrangement is a decompression pump, which on its inlet side is acted upon by an upstream concrete column under pressure, and in which the concrete is decompressed in portions, and only then is supplied to the application site.
According to a preferred embodiment of the invention the upstream concrete column is redirected at the outlet end of the downpipe into an upwardly directed, downwardly open cylinder, while the concrete portion separated from the concrete column exits downwardly from the cylinder.
In a further preferred embodiment of the invention it is envisioned that the upstream concrete column communicates alternatively at the outlet end of the downpipe with two separate cylinders, and from these is portioned in counterstroke and then delivered without pressure, in certain cases via the buffer container, to the application site.
It is first necessary to fill the downpipe with concrete, such that no demixing and no disruption occurs along the drop zone. In order to achieve this, the downpipe is first filled with water, before the concrete is introduced into the downpipe with the intermediate insertion of at least one sealing element. The water reaching the outlet side is then conveyed upwards, under the influence of the upstream concrete column, via a return pipe connected to the lower end of the downpipe and communicating therewith and preferably having a smaller diameter, or the water is discharged into the shaft.
For carrying out the inventive process, a device for concretization of deep, vertical shafts is provided, comprising a filling pump positioned above-ground and a downpipe connected to the filling pump, wherein the outlet end of the downpipe is connectable to a pressure-tight decompression pump, of which the outlet is in turn connectable with the application site. Preferably, a distribution hose leading to the application site and moveable by hand is connected to this outlet.
According to a preferred embodiment of the invention the decompression pump includes a pipe switch connectable with the outlet of the downpipe, of which the pipe switch outlet is alternatively connectable pressure-tight with one of two cylinders, of which the respective other cylinder communicates with an outlet or delivery conduit, preferably via a common buffer container, and wherein pistons are provided in the cylinder which pistons slide back and forth in opposition or counterstroke. The pipe switch is positioned in the buffer container below the downwardly open cylinders, and faces with its outlet upwards in the direction of the cylinder openings. On the other hand, the delivery conveyor from the decompression pump in the form of, for example, a distribution hose faces downwards, so that the decompressed concrete can be conveyed to the application site under the influence of gravity. In order to be able to carry out maintenance or servicing of the decompression pumps without having to disengage the concrete column from the downpipe, a sliding gate is provided in the downpipe ahead of the decompression pump.
Further, in accordance with a preferred embodiment of the invention, at the deepest point of the downpipe prior to the decompression pump, a closeable return pipe is connected in communication with the downpipe, preferably with smaller cross section than the downpipe. The return pipe serves for removing the water filled into the downpipe prior to the filling of the downpipe with concrete, removing the water upwards out of the shaft under the influence or pressure of the following concrete column. The water return thus occurs under the principle of the communicating pipes.
The invention is further concerned with a decompression pump for delivery of thick materials under pressure, in particular concrete, to an application site, in particular for the employment in a concretization process of the above-described type. The decompression pump exhibits in accordance with the invention a pipe switch which receives at the inlet side the thick material under pressure, which pipe switch is connectable at its outlet side alternatingly with one of two cylinders, of which the respective other cylinder is preferably in communication with an outlet via a common buffer container, and wherein two pistons are provided in the cylinders operating back and forth in counterstroke. The buffer container preferably includes on its floor a preferably downward facing outlet, onto which the distribution hose is connectable. Further, the buffer container is preferably provided with a pressure tight closeable servicing or maintenance opening.
With the above-described measures it is ensured that the pressure produced in the cement column is controlled or subordinated at any depth of the shaft, and that the delivery of the concrete occurs without problems. Advantageously for this purpose a control device can be provided for synchronizing the control of the filling pump and the decompression pump.